Dynamic memory allocation is generally used for managing memory dynamically at run time. Dynamic memory allocation can be used for allocating space for objects whose sizes and lifetimes are not known statically (i.e. at compile time). Unfortunately, dynamic memory allocators incur both execution time overhead and space overhead. Within some object oriented computer languages such as C and C++, dynamic memory allocation is achieved by functions such as malloc and free. However, such functions are not always sufficient. For example, the performance of these types of functions might not be sufficient for a particular application. Also, these types of functions generally do not provide garbage collection or persistent storage allocation in nonvolatile memory (e.g. disk storage).